Optical disks, magnetic disks and magnetooptical disks are increasingly popular mediums for digitally storing information. Such disks are typically enclosed in a box shaped disk cartridge having apertures through which a laser light source or magnetic head can read (or write) to the spinning disk contained within the cartridge.
In certain large-scale disk cartridge storage and retrieval systems (sometimes referred to as "jukeboxes"), disk cartridges are stored in one or more racks in an array of storage slots. Commonly, the slots are oriented horizontally and are arranged in a vertical column such that horizontal disk cartridges sit, one on top of another, in the individual slots. Storage and retrieval systems may have one or more such columns of disk cartridge storage slots. This type of system includes a cartridge retrieval mechanism which is movable into position adjacent a slot. The mechanism includes apparatus for grasping a cartridge while in the slot, drawing it out from the slot, holding the cartridge in a sleeve, transporting it to a different location, such as a recording/reading/erasing station, and ejecting the cartridge into that location.
Cartridges of the type used in present jukebox systems have two large nearly square faces which correspond to the top and bottom of the disk, and four thin rectangular faces which surround the disk and connect the top face to the bottom face. The cartridge has a shutter which slidably covers an aperture in one of the large faces and which provides a port through which the disk is presented to the central processing unit. The shutter is slidable to expose the disk contained inside the cartridge, for reading from or writing to the disk.
A portion of the shutter is slidable over one of the four thin faces and includes a catch which is automatically engaged at the reading/writing station to slide the shutter to expose the disk. The thin faces that are perpendicular to the thin face having the shutter catch are slightly tapered (at their ends nearest to the shutter) towards the shutter. The opposite ends of those faces have small rectangular notches that are sometimes used for disk handling.
In some jukebox systems cartridges of this type are loaded into portable cartridge magazines which can be easily installed into the jukebox systems. In such systems, a user loads a number of desired cartridges into the magazine, and inserts the entire magazine inside the jukebox system. The cartridge retrieval system is equipped to remove a selected cartridge directly from the magazine, and to return it to the magazine after use.
Cartridge magazines are normally rectangular boxes which have an open side through which cartridges are removed and inserted by a user or a cartridge retrieval system. It is necessary to provide a means for securing the cartridges within the magazine to prevent cartridges from falling out of the magazine through the open side. It is also necessary to provide means by which the magazine may be unlocked to permit insertion and removal of cartridges by a user or a cartridge retrieval system.
In one existing magazine design, the cartridges are stacked with the notches on each cartridge aligned with the notches on the other cartridges. A spring loaded retractable crossbar is biased so as to be in a locking position in which it engages the notches on one side of the cartridges, thereby preventing them from falling from the magazine. During installation of the magazine inside a compatible jukebox, a device inside the jukebox engages with the cross-bar and displaces the crossbar out of the cartridge notches so that the cartridge retrieval system can remove selected cartridges from the magazine. When the magazine is removed from the jukebox, the cross-bar springs back to its resting position within the cartridge notches, thereby re-locking the magazine.
The above-described magazine design may present problems during manual loading and unloading of cartridges. For example, removal of the cross-bar from the notches during manual loading and unloading requires manually holding the cross-bar in the unlocked condition (against the spring force). This requires the use of two hands, one for holding the cross-bar and the other for loading or unloading cartridges.
Another problem presented by cartridge magazines involves the need for proper orientation of the cartridges within the magazine. As discussed above, cartridges are provided with shutters that are slidable to expose the disk inside the cartridge for writing to, or reading from, the disk. It is therefore essential to load a cartridge into the jukebox in an orientation which will allow the cartridge retrieval mechanism to properly orient the disk in a read/write location.
It is also desirable to have a cartridge magazine that is easily assembled and that requires a minimal number of parts.
Accordingly, it is an object of the present invention to provide a magazine having a device for automatically unlocking cartridges within the magazine upon insertion of the magazine into a jukebox device, and for automatically locking the magazine upon its removal from the jukebox device.
If is a further object of the invention to provide a magazine having a device for manually unlocking the magazine for manual loading and unloading of cartridges, and for maintaining the unlocked condition of the magazine until loading or unloading is completed.
Another object of the present invention is to provide a cartridge magazine having a feature which prevents disks from being improperly inserted into the magazine (i.e. with the shutter facing in the wrong direction).
Still another object of the present invention is to provide a cartridge magazine that is easily assembled.